What's the end-game of this whole "sustainability" quest? Could the statement below be a North Star for what sustainability really means for us?
A sustainable global economy promotes prosperity while operating within the physical limits of a stable planet.
This sentence describes a world where humanity can continue to grow freely BUT ALSO will be steered back to a 'safe operating zone' that doesn't allow our behaviors put civilization at risk.
In order to appreciate what I mean, we need to cover a few concepts that are cornerstones of modern sustainability. The foundation of my claim is mostly inspired by the Planetary Boundary Framework, arguably the most profound publication in modern sustainability. It defines sustainability, not altruistically, but from rational observation — humanity needs a stable environment to have a good future.
Since its first publication in 2009, the Planetary Boundary Framework has reframed the worldview of sustainability (its third edition was just published in September 2023). It has achieved world-recognition, informed the United Nations Sustainable Development Goals (SDGs), and informs policy and target-setting practices.
The Planetary Boundary Framework is a “theory of relativity” for sustainability.
THE TAKEAWAY
Humans needs a stable planet to have a good future. Humanity has benefited from a stable planet since we developed into a modern civilization 10,000 years ago. This is a free subsidy that modern economics does not account for today.
Planetary Boundaries is the study of finding the scientific guardrails which can allow humans to maintain global environmental stability.
Tipping Points are thresholds that, once crossed, risk a chain-reaction in which Earth’s natural processes will rapidly break-down and no longer grant us the free subsidy of a stable environment.
A Sustainable Global Economy promotes human prosperity while incentivizing humans to operate within the physical limits of a stable planet.
Why does Humanity need a Stable Environment?
The Framework observes, through the study of 4 million years of human development and Earth Sciences, that society only developed into a modern civilization once the planet entered a period of environmental stability. Scientists call this period the Holocene.
Despite humans having already developed our current physical and cognitive abilities over 200,000 years ago, a hostile environment prevented the global population from growing beyond a few hundred thousand inhabitants.
The severe and erratic weather patterns were so difficult that our ancestors were forced to migrate from the highest peaks of Africa during the ice ages, to temperate grasslands in northern Greenland over only a few generations.
However, around 9,000 years ago, a “goldilocks'” period began. The average surface temperature stabilized and varied by less than ± 0.5° C. These serene conditions allowed for predictability, settlement, and farming. From there, human civilization was able to progress and accelerate to what it has become today.
This Environmental Stability is the worlds largest unaccounted for subsidy.
We are its unknowing beneficiaries.
The last 4 million years of average surface temperature was too volatile for humans to flourish until 9,000 years ago when the Earth’s temperature stabilized. Media Credit: Research Gate.
Planetary Boundaries
Understanding now that humans need environmental stability, we introduce new questions — What is the Earth doing to maintain stability? What causes instability?
The Planetary Framework asks the questions necessary to determine how to keep Earth in this “Holocene-like” state, but it also reveals an unsettling conclusion. It's takeaways can be summarized with three key concepts:
Earth Processes. Nine Earth Processes work together to self-regulate the global environment. Most are intuitive. For simplicity, I’ve listed 3 of them below. The full-table is at the bottom of this article, and on our resources page.
Climate. The process that regulates the average surface temperature of the planet. This allows water to be liquid and our bodies to function.
Ocean Acidification. The process which regulates the average acidity in the sea. This is why sea life and diversity exists.
Nitrogen Regulation. The process which regulates average nitrogen content in soil. This allows plants and agriculture to grow.
Planetary Boundaries. The health of each Earth Process can be determined by a few simple measurements. Just like measuring the RPMs of a motor pushed beyond its limits. Planetary Boundaries are operating limits which these processes can continue to be resilient and offer continued environmental stability. Push an Earth Process beyond this limit, and the process will wear down and break.
Earth processes are remarkably resilient. The natural carbon cycle of the earth freely absorbs almost 4 billion tons of additional human-created carbon. Nature wants to steer itself back to equilibrium!
Tipping Points. But… these processes only handle so much before reach their physical limits. They are characterized by a threshold behavior.
Once pushed beyond their limit (their tipping point), these processes reverse direction. Instead of pulling humanity back to equilibrium, they will turn and work against us.
Crossing tipping points risk triggering unstoppable chain-reactions and a permanent departure from environmental equilibrium.
The unsettling conclusion is this: Once tipping points are passed, the possibility of returning to a state of equilibrium becomes exponentially harder and less likely.
Why do Tipping Points occur?
In 2012, the Framework authors began publishing more extensive research on tipping points. This introduced a fourth concept called Tipping Elements: 16 large biophysical systems on the Earth that work together to create the Earth Processes that regulates the planet's temperature, carbon levels, ocean acidity etc…
If an Earth Process is an Engine, Tipping Elements are the parts of the engine that can be more closely examined for signs of wear and breakage.
These Tipping Elements are parts of our home planet that you will recognize: the Greenland Ice Sheet, the Amazon Rainforest, or the Australian Great Barrier Reef, to name a few. The full list is provided at the end of this article.
How does a Tipping Element 'tip'? Let’s use Arctic Winter Sea Ice as an example. As the white ice of the Arctic melts, the color of the Arctic changes from white to blue. The blue color absorbs more light and heat than the white color that was reflecting the light into space, thus creating an amplifying feedback loop that further accelerates warming and melting. If too much ice melts, the system ‘flips’ from a net-cooling system to a net-warming system for the global ecosystem.
Where are we Today? In 2012, only 1 Tipping Element showed signs of severe weakening. However when revisited in 2022, 9 of the 16 Tipping Elements showed material weakening. One Tipping Element — the Australian Great Barrier Reef — is likely already past its tipping point. The ocean, with less carbon absorption capacity and higher acidity, spells the eventual and permanent extinction for the reef system.
These systems are interconnected. As one process weakens and collapses, it exponentially shortens the survival of the other systems still trying to help us.
Media Credit: Potsdam Institute for Climate Impact Research. Figure by Biermann/PIK, based on Armstrong McKay et al, 2020
What is a Sustainable Global Economy?
With this context, let’s revisit my North Star statement and align it with this modern view of sustainability.
Let’s use a single market for simplicity – air travel. In a Sustainable Global Economy, the market will grow indefinitely to meet consumer demand; however when cumulative market activity puts pressure on one or more Planetary Boundaries, a sustainable economic system will apply an economic counter-pressure to steer free-market activity to innovate alternatives and de-risk permanent global destabilization.
Applied to all the markets globally, this would be a Sustainable Global Economy.
Unfortunately, how to apply this economic counter-pressure is beyond the scope of this article, but like all good North Stars, this article can provide:
A North Star: A fixed vision and objective that we directionally move towards
A Planetary Framework: A framework to measure collective progress towards this goal.
A Timeline: A way to measure how much time we have left based on the early-indicators of Tipping Elements.
The climate community has learned much over the last fifty years…
Perhaps we can shortcut the education process for newcomers by just starting here.
If you enjoyed this, please consider following, sharing, or connecting. I wrote this post first to share what steers my own exploration of science, technology, and financial systems to embark on "The Rewire".
Sincerely,
Logan
Planetary Boundaries
EARTH PROCESS
MEASURE
HOLOCENE
BASELINE
PLANETARY
BOUNDARY
TIPPING
POINT RISK
CURRENT
VALUE
Climate
Regulates the average surface temperature of the planet. (Allows water to be liquid and bodies to not overheat).
Atmospheric carbon dioxide concentration (ppm by volume)
280
ppm
350
ppm
450
ppm
417
ppm
Stratospheric Ozone
A process which maintains a chemical layer in the atmosphere that filters ultraviolet (UV) radiation which is harmful to surface-dwelling organisms (e.g. sunburns and DNA damage in plants, animals, and humans)
The O3 layer thickness measured in DU (Dobson Units)
290
DU
276
DU
261
DU
284
DU
Ocean Acidification
The process which regulates the average ocean acidity. These chemicals are necessary for shell and skeleton development in sea life.
Average global carbonate ion concentration
(Ω arag)
3.44
Ω arag
2.80
Ω arag
2.75
Ω arag
2.80
Ω arag
Freshwater Exchange
The process which Freshwater is exchanged and generated to support all life. This is broken into Blue Water (related to stream and surface water) and Green Water (which is root-soil and plant accessible water).
(%) Of global ice-free streamflow land area.
9.4%
10.2%
50%*
*Provisional
18.2 %
(%) Of global ice-free root-zone soil moisture land area.
9.8%
11.1%
50%*
*Provisional
15.8%
Land Systems
Human alteration to the proportion of global forests vs. other land-types (this is a weighted average of tropical, temperate, and boreal forest coverage).
% of global forest cover relative to pre-industrial forest cover.
100%
70%
54%
60%
Biosphere Integrity
The functional biological interactions which support life (such as be pollination, habitat maintenance and more). Biological integrity requires both genetic and functional diversity.
Genetic Diversity.
Extinctions per Million species-years. (E/MSY)
100%
E/MSY
70%
E/MSY
54%
E/MSY
60%
E/MSY
Photosynthetic energy available to ecosystems measured in Net Primary Production (NPP) as a % of the pre-industrial Holocene NPP levels (HANPP).
1.9%
HANPP
10%
HANPP
20%
HANPP
30%
HANPP
Biogeochemical Flow
The process which regulates the concentration of chemicals (particularly Phosphorous and Nitrogen) in soil necessary for plant life and agriculture.
Nitrogen outflows.
(N/yr)
0
Tg of N/yr
62
Tg of N/yr
82
Tg of N/yr
190
Tg of N/yr
Phosphorous outflows (P/yr)
0
Tg of P/yr
6.2
Tg of P/yr
11.2
Tg of P/yr
17.2
Tg of P/yr
Novel Entity Introductions
The Introduction of synthetic chemicals and entities released into the environment that have toxic and negative effects (entities such as Plastics, Radioactive Contamination, and Heavy Metals).
In accordance to the Montreal Protocol:
Novel Entity measures are defined on a case by case basis and should not be introduced into the environment unless it has been certified as harmless and is monitored.
Transgressed
Additional Resources
The Official 2023 Planetary Boundaries Paper: Earth beyond six of nine planetary boundaries
TED: Johan Rockström introduces Tipping Points in his own words (7 minutes)
Let's Talk Climate Solutions Part I: The Science of Climate Change (50 minutes)
Breaking Boundaries a Netflix Documentary on Tipping Points (1h 14m)
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